Change from 1/2 to 3/4 valve

I'm converting a bathtub to a shower only. The old valve is 1/2" but I'd like to install a 3/4" valve to improve water flow. Can this be done and will it make a difference or should I just stick to the 1/2" valve? The new shower unit will have a fixed riser and a handheld sprayer. The main pipes coming into the bath are 3/4".
Thanks.

3/4"

Unless you are using special shower heads, they will be flow limited so the only advantage would be if it is also a tub filler in which case you would fill the tub faster.